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XMPP is as secure as Signal nowadays, it implements the same encryption scheme and is still completely federated: https://conversations.im/omemo/ https://conver

XMPP is as secure as Signal nowadays, it implements the same encryption scheme and is still completely federated: https://conversations.im/omemo/ https://conversations.im/omemo/ Omemo is a relatively recent effort though and many people still remember the days when gpg and otr where the sad state of the art in the xmpp world.

rakoo 5y ago
XMPP leaves a lot of metadata and user information around, so it does have a privacy issue that's probably not solvable. Whether it's a security issue is a completely different discussion though.
- f1refly 5y ago
  That's got nothing to do with the security problems OP complained about though. Are there even working solutions to those metadata problems apart from sending dummy decoy messages and purposeful delays on the server side to make correlating message relaying hard?
  - southerntofu 5y ago
    The metadata leaks are more about correlating pseudonymous identities to the same accounts than network leaks (for which we employ VPN/SSH tunnels or Tor). If you'd like to know more about the threat model of XMPP: https://joinjabber.org/faqs/security/ https://joinjabber.org/faqs/security/ (critique welcome)
infosechandbook 5y ago
> XMPP is as secure as Signal nowadays, it implements the same encryption scheme Signal enforces E2EE, you can't disable it. If XMPP supports E2EE depends on the XMPP clients and servers, so it isn't enforced and can be disabled. Server admins can even inject XMPP messages that look like coming from the legitimate sender. This is far from "secure as Signal."
- zaik 5y ago
  > Server admins can even inject XMPP messages that look like coming from the legitimate sender. How should that be possible if OMEMO is enabled (which is the default in more modern clients)?
  - infosechandbook 5y ago
    > How should that be possible if OMEMO is enabled (which is the default in more modern clients)? See https://infosec-handbook.eu/articles/xmpp-aitm/#t5 https://infosec-handbook.eu/articles/xmpp-aitm/#t5 TL;DR: XMPP clients can't distinguish between legitimate and injected messages, even if OMEMO is enabled. The XMPP client just displays injected messages as an unencrypted message from the sender.
    - zaik 5y ago
      In Conversations unauthenticated messages are displayed with a red background, whereas OMEMO authenticated messages are displayed in green. They do not look the same.
      - infosechandbook 5y ago
        Nobody claimed that they look the same. As mentioned in the linked article, the behavior upon receiving an injected message is client specific. In any way, the injected message is somehow presented to the (non-technical) user who might then be targeted. We all know the same problem exists in the e-mail world.
        MattJ100 5y ago
        Signal operators can also inject messages to people. So this is a strange comparison. What holds true in both systems is that if someone does this, it's detectable thanks to E2EE. Which is the entire point of E2EE.
        5y ago

rakoo 5y ago

XMPP leaves a lot of metadata and user information around, so it does have a privacy issue that's probably not solvable. Whether it's a security issue is a completely different discussion though.

f1refly 5y ago
That's got nothing to do with the security problems OP complained about though. Are there even working solutions to those metadata problems apart from sending dummy decoy messages and purposeful delays on the server side to make correlating message relaying hard?
- southerntofu 5y ago
  The metadata leaks are more about correlating pseudonymous identities to the same accounts than network leaks (for which we employ VPN/SSH tunnels or Tor). If you'd like to know more about the threat model of XMPP: https://joinjabber.org/faqs/security/ https://joinjabber.org/faqs/security/ (critique welcome)

infosechandbook 5y ago

> XMPP is as secure as Signal nowadays, it implements the same encryption scheme Signal enforces E2EE, you can't disable it. If XMPP supports E2EE depends on the XMPP clients and servers, so it isn't enforced and can be disabled. Server admins can even inject XMPP messages that look like coming from the legitimate sender. This is far from "secure as Signal."

zaik 5y ago
> Server admins can even inject XMPP messages that look like coming from the legitimate sender. How should that be possible if OMEMO is enabled (which is the default in more modern clients)?
- infosechandbook 5y ago
  > How should that be possible if OMEMO is enabled (which is the default in more modern clients)? See https://infosec-handbook.eu/articles/xmpp-aitm/#t5 https://infosec-handbook.eu/articles/xmpp-aitm/#t5 TL;DR: XMPP clients can't distinguish between legitimate and injected messages, even if OMEMO is enabled. The XMPP client just displays injected messages as an unencrypted message from the sender.
  - zaik 5y ago
    In Conversations unauthenticated messages are displayed with a red background, whereas OMEMO authenticated messages are displayed in green. They do not look the same.
    - infosechandbook 5y ago
      Nobody claimed that they look the same. As mentioned in the linked article, the behavior upon receiving an injected message is client specific. In any way, the injected message is somehow presented to the (non-technical) user who might then be targeted. We all know the same problem exists in the e-mail world.
      - MattJ100 5y ago
        Signal operators can also inject messages to people. So this is a strange comparison. What holds true in both systems is that if someone does this, it's detectable thanks to E2EE. Which is the entire point of E2EE.
        5y ago